Databases

Select the databases prefix.

Script Parameter:UXANALYZE.MODELING_PREFIX

Select the group to read the measurement from the list of groups in the Target database.

Script Parameter:UXANALYZE.TARGETGROUP

Specify the group to write the inversion results from the list of groups in the Source database.

Script Parameter:UXANALYZE.SOURCEGROUP

Select the ID channel from the list of channels in the Target database.

Default: UXA_Target_ID

Script Parameter:UXANALYZE.TARGETID

Select the mask channel that selects/deselects measurements to invert from the list of channels in the Target database.

Default: UXA_Mask

Script Parameter:UXANALYZE.TARGETMASK

Select the sensor channel to use in the inversion from the list of channels in the Data database.

Script Parameter:UXANALYZE.SENCHAN

Select the low and high time gates from the list, which limit the range of data used when modelling the data.

Default value for low gate is the one with the first valid time (UXA_GateFirstValidTime).

Default value for high gate is the maximum number of gates minus one.

Script Parameters:

UXANALYZE.Static_LoGate

UXANALYZE.Static_HiGate

Select the maximum number of dipoles to invert.

This determines how many sources will be modeled. For example, if the number of dipoles selected is 3, a total of 6 sources will be calculated, one 1-dipole, two 2-dipole, and three 3-dipole.

In the Source database, the Target ID of each source follows this pattern: [FLAG]_[MEASUREMENT]_[SOLVER][SOURCE].

If flag ID is 79 and measurement ID is 1, number of dipoles value of 3 generates the following sources: 79_001_11, 79_001_21, 79_001_22, 79_001_31, 79_001_32, and 79_001_33.

Default value is 1.

Script Parameter:UXANALYZE.NDIPOLE_SOLVER

Specify the Chi squared threshold.

As part of the inversion process, the Pearson's cumulative test statistic is calculated and saved in the subset database under UXA_CHI2 channel (see the Application Notes).

The Transmitter and Receiver combinations that exceed the “Chi2 threshold” are tabulated in the Source database (UXA_CHI2_ABOVETHRESH). In addition these combinations are highlighted with yellow on the Decay Display Measured vs Modeled plots.

Script Parameter:UXANALYZE.CHI2THRESHOLD

The target ID. This ID field is composed of four parts:

• Geo ID
• Flag ID
• Measurement ID
• Source ID

Each part is delimited by an underscore (_).

The Chi-Squared test metric – a measure of the how well the model data match the observed data for all Transmitter (TX) and Receiver (RX) combinations.

The Pearson Chi-Square is calculated across the entire time window for all TX-RX combinations. The value of the Chi-Square test statistic is:

Where:

x²= Pearson's cumulative test statistic, which asymptotically approaches a x² distribution.

O_i = observed or measured data;

E_i = expected or modeled data;

n = the number of valid time gates.

This measure fit is for all the data for a single flag (as opposed to the Chi-square in the Subset database is the individual RX-TX combinations).

The fit coherence metric, the correlation coefficient squared – a measure of the how well the model data match the observed data for all Transmitter (TX) and Receiver (RX) combinations.

The value of the correlation coefficient squared is:

Where:

ρ = Pearson's correlation coefficient.

O_i = observed or measured data;

E_i = expected or modeled data;

σ_O = standard deviation of the observed data;

σ_E = standard deviation of the expected data;

n = the number of valid time gates.

A high fit coherence does not guarantee that the fit results are accurate – only that the match between modeled and measured data is high. A fit coherence of 0.8 or less indicates poor inversion the results and should not be use for analysis.

Inversion or model error, a measure off the error in the inversion as a percentage.

Error flag:

• 0: Fit converge successfully
• 1:  Unexpected or general error
• 2: Maximum number of iterations reached

The polarizabilities (or sometime “betas”), primary, secondary and tertiary.

These are the three response coefficients, that represent the eigenvalues of the magnetic polarizability tensor. They can be thought of as components along the three orthogonal axes of the induced dipole. Negative values are physically impossible.

The relative size of the coefficients provides information about the shape of the object. For an isolated metallic object:

• Cylindrical shape, B1>B2≈B3.
• Spherical shape, B1≈B2≈B3.
• Plate shape, B1≈B2>B3

The number of the TX-RX combinations (see the Subset database) where the UXA_CHI2 are above the Chi2 threshold.

In addition, these combinations are highlighted with yellow on the Decay Display Measured vs Modelled plots.

The background sensor noise channel.

The background noise channel, UXA_Noise_Floor, is created when have repeated background data from the same time period and Level Advanced Sensor Data is executed.